In a major blow to one of the world’s most powerful tech companies, a U.S. federal court has ruled that Google broke antitrust laws by monopolising key parts of the digital advertising market.
Judge Leonie Brinkema of the Eastern District of Virginia found that Google had “willfully acquired and maintained monopoly power” in two critical areas of online advertising: publisher ad servers and ad exchanges. The court also concluded that Google unlawfully tied these services together, violating Sections 1 and 2 of the Sherman Act.
“The plaintiffs have proven that Google acted unlawfully in maintaining dominance in these markets,” Judge Brinkema wrote in her opinion, released last Thursday.
The ruling comes after a three-week bench trial involving the U.S. Department of Justice and 17 states. While the plaintiffs failed to prove Google had monopolised the market for advertiser ad networks, they secured a landmark victory on the other counts.
A Market Built on Speed and Surveillance
Digital advertising today is a hyperfast, automated world. When you visit a webpage, a split-second auction takes place behind the scenes to determine which ad appears in front of you. That auction — and the systems managing it — is what this case was all about.
Google operates the dominant tools on both sides of this exchange: it provides DFP, the ad server most online publishers use to sell ad space, and AdX, the ad exchange that connects publishers to advertisers. It also runs DV360, the tool advertisers use to bid in these auctions.
The court found that Google gave its own exchange preferential access to the ad space managed by its publisher server, limiting competition and harming rival ad exchanges.
“The glue that sealed Google’s dominance was its ability to connect its publisher and advertiser services through AdX,” said the judge, citing internal emails and witness testimony from across the industry.
What Google Did — and Why It Matters
The court said Google tied together its products in a way that forced publishers and advertisers into its ecosystem. Publishers wanting access to Google’s massive pool of advertisers had little choice but to use DFP. At the same time, advertisers using Google’s tools were pushed toward buying through AdX.
This closed loop shut out competitors, raised costs, and potentially reduced revenue for online publishers — including news outlets — that depend on advertising income to survive.
Industry insiders have long complained about Google’s dominance in the ad tech stack. A former executive at a rival exchange testified that Google’s practices “left crumbs for everyone else.” Several publishers, including Gannett, The New York Times, and the Daily Mail, gave evidence describing the lack of viable alternatives.
What Happens Now?
The court has not yet decided how to remedy Google’s violations, but Judge Brinkema has ordered a separate hearing to determine next steps.
Remedies on the table include breaking up parts of Google’s ad business — particularly its ad exchange and publisher tools — and imposing strict limitations on how Google can integrate its products.
“This ruling sends a clear message: even the most powerful tech companies are not above the law,” said Jonathan Kanter, Assistant Attorney General for the DOJ’s Antitrust Division.
Google, for its part, has denied wrongdoing and is expected to appeal.
“We disagree with the court’s decision and will defend our business model, which helps publishers and advertisers thrive in a competitive ecosystem,” a spokesperson for the company said in a statement.
A Turning Point for Big Tech?
This case is one of the most significant antitrust decisions against a tech company in decades. While other suits — including those targeting Google Search and Apple’s App Store — are still ongoing, this decision marks a concrete legal victory for regulators seeking to rein in Silicon Valley.
Experts say the ruling could reshape the future of online advertising.
“If the remedies are strong enough, we may finally see a fairer market where publishers and advertisers get more value and have real choices,” said Dina Srinivasan, a fellow at Yale Law School who studies digital monopolies.
The case, officially known as United States et al. v. Google LLC, now moves into its final phase. All eyes will be on what the court decides to do next — and whether Google will be forced to dismantle parts of its empire.
